LAUSR

High amounts of grains in the equine diet led to high starch intake, causing gut alterations. Aimed at reducing harmful effects, Macleaya cordata extract (MCE) is a phytogenic additive that stands out for its antibiotic and anti-inflammatory effects proven in different species. However, there is no useful information for horses. The objective of this study was to evaluate the effects of different levels of the inclusion of commercial MCE on body weight (BW), body condition score (BCS), total apparent digestibility (AD) of nutrients, faecal pH and fermentative products, on ponies fed a high-starch diet. Eight healthy gelding Mini Horse ponies were used. The study design was contemporary double Latin-square 4 × 4 in the experimental unit, with the animal inside each experimental period (n = 8 experimental units per group). The experiment was conducted over four 20-d periods. Basal diet attended 1.75% BW dry matter daily and starch intake was 2.2 g/kg BW/meal. The experimental groups were as follows: control - without food additive; S1-1 mg/kg BW MCE; S1.5-1.5 mg/kg BW MCE and S2-2 mg/kg BW MCE. The data were analysed by PROC MIXED of SAS (p < 0.05). Tendency was considered when 0.05 < p < 0.1. Our results showed higher ether extract (EE) AD for S2 group (63.75%) when compared with the control (54.55%) (p = 0.0377). Lactate was lower (p = 0.0391) in S1 (3.27 mmol/l) and S2 (3.24 mmol/l) groups, although pH was not different between groups. Iso-valerate was greater in S1 group (2.29 mmol/l; p = 0.0289), and a tendency of higher butyrate values was found for S1 and S2 groups (p = 0.0980). We concluded that MCE supplementation probably positively influences equine resident microbiota, improving EE AD and increasing iso-valerate concentration. It can also minimise harmful high-starch impact. We recommend further studies using MCE in horses for a better understanding of its local activity and possible benefits.